Two
color gifs are capable of making powerful visual statements,
with relatively small fast loading files.

Using
an Error Diffusion setting during color depth reduction creates
the dots.
How we light our images beforehand, greatly influences how those
dots will be arranged.
Altering our lighting before decreasing color depth enables various
looks.

I played
around with a photo, but my 2-color image was pretty much unrecognizable
with only 2 colors?

When preparing
images for two color reductions, experiment with emphasizing
your Highlights and Shadows, and by increasing sharpness &
contrast (via Unsharp Mask & Clarify). A real key is having
all images properly prepared prior to running many procedures,
special effects, or filters.

This means
becoming better acquainted with all your features on the Colors
> Adjust menu, along with those Enhance Photo tools on the
Effects Menu.

One of the
easiest beginner tools for two-color reductions is Highlight
Midtone Shadow, on the Colors menu. In fact, that little fella
was the only tool I was using exclusively back in PSP5, while
learning many favorite tricks. Back then, there weren't any goodies
like Curves, Levels, Adjustment Layers, or Enhance Photo tools.
We also didn't have any food to eat. I was forced
to walk barefoot through waist deep snow over broken glass for
art supplies. When I eventually did return home, our cable TV
only had a measly 80 channels. Back in '98 life was hell,
and you youngsters just don't appreciate how easy you've got
it today :)

Highlight
Midtone Shadow: Try
increasing the Shadow , while decreasing the setting for Highlight.
Have the LINEAR method ticked.

These days,
my favorite tool for this job is Curves. Kris usually
seems partial to the Histogram Adjustment. (see next column),
but I personally love my Curves. Either that version found
on the Colors Adjust menu, or its cousin down in the layer palette
(also found on the Layers menu under New Adjustment Layer).

New Adjustment
Layer:
Either Curves or Levels. The Curves one would be at the
very top of my list as the primo tool for playing and tweaking,
prior to two-color reductions. Tweak with Curves, then
duplicate the image, reducing that duplicate down to two colors.
No need for flattening the duplicate, since our colors reduction
automatically flattens at the same darned time. Meanwhile, we've
still got the original to experiment and play with. Double-click
a New Adjustment layer in the layer palette to re-edit any of
your current settings and to make an updated duplicate.
It's easy to whip up a bunch of fast duplicates and to compare
the results.

Enhance
Photo stuff
found on the Effects menu, offers plenty of useful edge enhancement
opportunities that work great with this stuff. That Clarify
is a nifty little devil who is absolutely amazing for emphasizing
& contrasting many edges prior to two color reductions.

First of all,
start by converting your image to greyscale then do your reduction
to two colors. Look at the resulting image and see why it is
unrecognizable. Most likely it is one (or both) of two things:

(1) the image
is not contrasty enough and
(2) the grey shades are wrong.

Item 1 means
that if your image is all various shades of grey you won't end
up with a dark object on a light background but you'll get dots
all over the place.

This can be
fixed by compressing midtones in Histogram Adjustment. Item 2
means this. If you have a mid grey of 128 it will be about 50%
black dots on a white background after color reduction. If you
want more dense dots in that region of the image, you must make
the region darker. If you want fewer dots, you must make the
region lighter.

The Gamma
control in Histogram Adjustment does this. If you want pure white without any dots (say
in the image background) use the High Clip Limit control in Histogram Adjustment to make this portion
of the image white before color reduction. If you want a solid
black somewhere in the image, use the Low Clip Limit to achieve it. One
other thing, though it is less useful. If you want to have widely
spaced dots throughout your image, you can slide Output Min up
and Output Max down in Histogram Adjustment. -Kris

Kris and I frequently travel very different roads to reach similar
destinations. My take on the Histogram Adjustment isn't
nearly as precise or clinical - nonetheless, it still yields
pretty darned great pictures. If you are intimidated by
all those spinning numbers and choices? Don't be!
Below is an alternative for bypassing a lot of the Histogram
Adjustment's techno-mystique.

Crack
open a big bag of chips, and uncork yourself a soda.
Keep dragging those settings and levers around,AS YOU CLOSELY WATCH ALL YOUR RESULTING PREVIEWS.What happens if you drag some of those guys to the left?
What happens when he goes over to the right?

Ignore
all fear of spinning numbers and intimidation of graphs.JUST MOVE STUFF AROUND AND WATCH THOSE PREVIEWS!
Keep hitting your reset, to begin again fresh from scratch.
That's it, that's all, it is truly that easy.

PAY
ATTENTION THERE MAN!
WHAT ARE YOUR OWN EYEBALLS TELLING YOU?There
you go - that is exactly what it does!
It's not the least bit complicated at all.

Snap out of
it. Stop all whining, sniveling and cowering. We all honestly
need to make our peace with this incredible tool. Just
keep dragging all your stuff around and watching your previews.
It won't be long before all things are revealed. If you
aren't high fiving yourself, and singing "hot damn"
by bedtime? Then you didn't eat the chips, or you uncorked
too darned many sodas. In which case, sober up, and try
it again tomorrow. It isn't complicated at all. It
only looks that way, when we feel intimidated. Stop peeing
those pants. These are only dials, and they cannot hurt
you. Jump in there to drag them, to spin them, and to drive
them around the block. Look and listen to what your previews
are telling you. Stop skittering around it, and
fretting over it. Just do it -> you'll be glad you did.
-Porter

Oh
my God, help me Rhonda!
What does all that mean?
Histogram Adjustment Guy still feel a wee bit intimidating to you? Consider: